Geoff Ghose wonders about these questions too -- but he's a neuroscientist, so he gets to try to answer them. And after he published new research in the journal PLOS Biology at the end of October, some science writers started speculating that down the road, Ghose's findings could lead to pills that alter how we perceive time.

The research started about four years ago, when Ghose, along with one of
his then-students, Blaine Schneider, wanted to look at how the brain
keeps time.

"We look at a clock or a watch or sunlight," Ghose explains. "But we also have a thing separate from that, like 'Gee, it's getting late,'" an
innate ability to distinguish between a minute and an hour, or a day.

These
are big questions, and other scientists had looked at them before.
Those researchers had found that in monkey brains, neuron activity
builds over time, until it finally reaches a point that signals, for
instance, 'It's time to go.'

But in many of those experiments, the
monkeys would also get rewarded. Ghose and Schneider speculated that
this impending reward could be triggering an anticipation build-up that
skewed results away from just measuring time-tracking.

So they devised an experiment in which monkeys could only get a task right by
keeping time, and in which they didn't have any outside help to generate
a timing pattern.

The scientists worked with two rhesus macaque
monkeys, and trained them to move their eyes between dots on a screen at
regular one-second intervals. After three months, the monkeys could
keep the time within fractions of a second.

Here's the
breakthrough: Using electrodes to eavesdrop on the monkeys' brains, the
researchers found that neuron activity actually decreased -- not
increased, like previous results -- between each interval, and that the
more activity dropped, the faster the monkeys were.

In
other words, the monkeys' sense of time was linked to the activity they
were doing, and those neuron circuits, as opposed to some general brain
clock. "The animals' relationship to timing actually switched depending on the particular task the animal was doing," Ghose explains. "It's not consistent with a single clock mechanism." That is, the brain has time zones.

So what practical applications
does this have? One idea is that every activity might have its own
highly precise neuron decay rate, and that training can hone this
task-specific time keeping. For instance, a drummer might improve his
rhythm through practice, but still have poor timing during other tasks.

"It might be that you just make a small population of neurons that are appropriate for the task really good," says Ghose. "That's a fundamentally different notion of how you get good at things, how you learn things."

Ghose
plans on devoting his next experiments to unpacking the question of how
this kind of precision, like rhythm, develops -- i.e., what's going on
in the monkeys' brains while they're learning to keep these intervals --
and how flexible it is.

From a macro perspective, learning
more about how and why neuron activity is linked to time could translate
into a better understanding of why neurodegenerative diseases, like
Parkinson's, can skew a person's sense of time.

Figuring out "how the brain represents information is the first step," says Ghose.

The new research also hints at explaining the staple "time flies when
you're having fun" saying. Hormones like adrenaline are known
to affect how neuron activity decays. If this decay rate is linked to
our sense of what time it is, it follows that it could be possible to play with these hormonal signals in order to alter our perceptions.

Some
popular science writers are latching onto this to take these results even further. "As the
findings unfold, it ought to be possible to manipulate these states to
change how time is perceived," writes Mother Nature Network.
"In other words, in the future there may actually be pills you can take
to alter your perception of time just like there are mind-altering
pills for various other purposes."

Ghose cautions that this is
speculative. "A pill has a diffuse effect on a lot of neurons in the
brain," he says, in contrast to his findings, which show
results linked to very specific neurons. Which is to say, when it comes
to the mysteries of time, "Looking for a pill might not even be the
right way to think about things."